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#include "precomp.hpp"

/****************************************************************************************\

   calculate image homography

\****************************************************************************************/

CV_IMPL void
cvCalcImageHomography( float* line, CvPoint3D32f* _center,
					   float* _intrinsic, float* _homography ) {
	double norm_xy, norm_xz, xy_sina, xy_cosa, xz_sina, xz_cosa, nx1, plane_dist;
	float _ry[3], _rz[3], _r_trans[9];
	CvMat rx = cvMat( 1, 3, CV_32F, line );
	CvMat ry = cvMat( 1, 3, CV_32F, _ry );
	CvMat rz = cvMat( 1, 3, CV_32F, _rz );
	CvMat r_trans = cvMat( 3, 3, CV_32F, _r_trans );
	CvMat center = cvMat( 3, 1, CV_32F, _center );

	float _sub[9];
	CvMat sub = cvMat( 3, 3, CV_32F, _sub );
	float _t_trans[3];
	CvMat t_trans = cvMat( 3, 1, CV_32F, _t_trans );

	CvMat intrinsic = cvMat( 3, 3, CV_32F, _intrinsic );
	CvMat homography = cvMat( 3, 3, CV_32F, _homography );

	if ( !line || !_center || !_intrinsic || !_homography ) {
		CV_Error( CV_StsNullPtr, "" );
	}

	norm_xy = cvSqrt( line[0] * line[0] + line[1] * line[1] );
	xy_cosa = line[0] / norm_xy;
	xy_sina = line[1] / norm_xy;

	norm_xz = cvSqrt( line[0] * line[0] + line[2] * line[2] );
	xz_cosa = line[0] / norm_xz;
	xz_sina = line[2] / norm_xz;

	nx1 = -xz_sina;

	_rz[0] = (float)(xy_cosa * nx1);
	_rz[1] = (float)(xy_sina * nx1);
	_rz[2] = (float)xz_cosa;
	cvScale( &rz, &rz, 1. / cvNorm(&rz, 0, CV_L2) );

	/*  new axe  y  */
	cvCrossProduct( &rz, &rx, &ry );
	cvScale( &ry, &ry, 1. / cvNorm( &ry, 0, CV_L2 ) );

	/*  transpone rotation matrix    */
	memcpy( &_r_trans[0], line, 3 * sizeof(float));
	memcpy( &_r_trans[3], _ry, 3 * sizeof(float));
	memcpy( &_r_trans[6], _rz, 3 * sizeof(float));

	/*  calculate center distanse from arm plane  */
	plane_dist = cvDotProduct( &center, &rz );

	/* calculate (I - r_trans)*center */
	cvSetIdentity( &sub );
	cvSub( &sub, &r_trans, &sub );
	cvMatMul( &sub, &center, &t_trans );

	cvMatMul( &t_trans, &rz, &sub );
	cvScaleAdd( &sub, cvRealScalar(1. / plane_dist), &r_trans, &sub ); /* ? */

	cvMatMul( &intrinsic, &sub, &r_trans );
	cvInvert( &intrinsic, &sub, CV_SVD );
	cvMatMul( &r_trans, &sub, &homography );
}

/* End of file. */

